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Genetics Home Reference: your guide to understanding genetic conditions
http://ghr.nlm.nih.gov/     A service of the U.S. National Library of Medicine®

22q11.2 duplication

Reviewed January 2015

What is 22q11.2 duplication?

22q11.2 duplication is a condition caused by an extra copy of a small piece of chromosome 22. The duplication occurs near the middle of the chromosome at a location designated q11.2.

The features of this condition vary widely, even among members of the same family. Affected individuals may have developmental delay, intellectual disability, slow growth leading to short stature, and weak muscle tone (hypotonia). Many people with the duplication have no apparent physical or intellectual disabilities.

How common is 22q11.2 duplication?

The prevalence of the 22q11.2 duplication in the general population is difficult to determine. Because many individuals with this duplication have no associated symptoms, their duplication may never be detected.

Most people tested for the 22q11.2 duplication have come to medical attention as a result of developmental delay or other problems affecting themselves or a family member. In one study, about 1 in 700 people tested for these reasons had the 22q11.2 duplication. Overall, more than 60 individuals with the duplication have been identified.

What are the genetic changes related to 22q11.2 duplication?

People with 22q11.2 duplication have an extra copy of some genetic material at position q11.2 on chromosome 22. In most cases, this extra genetic material consists of a sequence of about 3 million DNA building blocks (base pairs), also written as 3 megabases (Mb).

The 3 Mb duplicated region contains 30 to 40 genes. For many of these genes, little is known about their function. A small percentage of affected individuals have a shorter duplication in the same region. Researchers are working to determine which duplicated genes may contribute to the developmental delay and other problems that sometimes affect people with this condition.

Related Chromosome(s)

Changes involving this chromosome are associated with 22q11.2 duplication.

  • chromosome 22

Can 22q11.2 duplication be inherited?

The inheritance of 22q11.2 duplication is considered autosomal dominant because the duplication affects one of the two copies of chromosome 22 in each cell. About 70 percent of affected individuals inherit the duplication from a parent. In other cases, the duplication is not inherited and instead occurs as a random event during the formation of reproductive cells (eggs and sperm) or in early fetal development. These affected people typically have no history of the disorder in their family, although they can pass the duplication to their children.

Where can I find information about diagnosis or management of 22q11.2 duplication?

These resources address the diagnosis or management of 22q11.2 duplication and may include treatment providers.

  • Gene Review: 22q11.2 Duplication (http://www.ncbi.nlm.nih.gov/books/NBK3823)
  • Genetic Testing Registry: 22q11.2 duplication syndrome (http://www.ncbi.nlm.nih.gov/gtr/conditions/C2675369)

You might also find information on the diagnosis or management of 22q11.2 duplication in Educational resources (http://ghr.nlm.nih.gov/condition/22q112-duplication/show/Educational+resources) and Patient support (http://ghr.nlm.nih.gov/condition/22q112-duplication/show/Patient+support).

General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about 22q11.2 duplication?

You may find the following resources about 22q11.2 duplication helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for 22q11.2 duplication?

  • chromosome 22q11.2 duplication syndrome
  • chromosome 22q11.2 microduplication syndrome

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about 22q11.2 duplication?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/gard).

What glossary definitions help with understanding 22q11.2 duplication?

autosomal ; autosomal dominant ; cell ; chromosome ; developmental delay ; disabilities ; disability ; DNA ; duplication ; hypotonia ; inherit ; inheritance ; inherited ; Mb ; muscle tone ; population ; prevalence ; reproductive cells ; short stature ; sperm ; stature ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).

References

  • Courtens W, Schramme I, Laridon A. Microduplication 22q11.2: a benign polymorphism or a syndrome with a very large clinical variability and reduced penetrance?--Report of two families. Am J Med Genet A. 2008 Mar 15;146A(6):758-63. doi: 10.1002/ajmg.a.31910. (http://www.ncbi.nlm.nih.gov/pubmed/18260141?dopt=Abstract)
  • Gene Review: 22q11.2 Duplication (http://www.ncbi.nlm.nih.gov/books/NBK3823)
  • Mukaddes NM, Herguner S. Autistic disorder and 22q11.2 duplication. World J Biol Psychiatry. 2007;8(2):127-30. (http://www.ncbi.nlm.nih.gov/pubmed/17455106?dopt=Abstract)
  • Ou Z, Berg JS, Yonath H, Enciso VB, Miller DT, Picker J, Lenzi T, Keegan CE, Sutton VR, Belmont J, Chinault AC, Lupski JR, Cheung SW, Roeder E, Patel A. Microduplications of 22q11.2 are frequently inherited and are associated with variable phenotypes. Genet Med. 2008 Apr;10(4):267-77. doi: 10.1097/GIM.0b013e31816b64c2. (http://www.ncbi.nlm.nih.gov/pubmed/18414210?dopt=Abstract)
  • Portnoï MF. Microduplication 22q11.2: a new chromosomal syndrome. Eur J Med Genet. 2009 Mar-Jun;52(2-3):88-93. doi: 10.1016/j.ejmg.2009.02.008. Epub 2009 Feb 28. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19254783?dopt=Abstract)
  • Ramelli GP, Silacci C, Ferrarini A, Cattaneo C, Visconti P, Pescia G. Microduplication 22q11.2 in a child with autism spectrum disorder: clinical and genetic study. Dev Med Child Neurol. 2008 Dec;50(12):953-5. doi: 10.1111/j.1469-8749.2008.03048.x. (http://www.ncbi.nlm.nih.gov/pubmed/19046189?dopt=Abstract)
  • Torres-Juan L, Rosell J, Morla M, Vidal-Pou C, García-Algas F, de la Fuente MA, Juan M, Tubau A, Bachiller D, Bernues M, Perez-Granero A, Govea N, Busquets X, Heine-Suñer D. Mutations in TBX1 genocopy the 22q11.2 deletion and duplication syndromes: a new susceptibility factor for mental retardation. Eur J Hum Genet. 2007 Jun;15(6):658-63. Epub 2007 Mar 21. (http://www.ncbi.nlm.nih.gov/pubmed/17377518?dopt=Abstract)
  • Wentzel C, Fernström M, Ohrner Y, Annerén G, Thuresson AC. Clinical variability of the 22q11.2 duplication syndrome. Eur J Med Genet. 2008 Nov-Dec;51(6):501-10. doi: 10.1016/j.ejmg.2008.07.005. Epub 2008 Jul 29. (http://www.ncbi.nlm.nih.gov/pubmed/18707033?dopt=Abstract)
  • Yu S, Cox K, Friend K, Smith S, Buchheim R, Bain S, Liebelt J, Thompson E, Bratkovic D. Familial 22q11.2 duplication: a three-generation family with a 3-Mb duplication and a familial 1.5-Mb duplication. Clin Genet. 2008 Feb;73(2):160-4. Epub 2007 Dec 12. (http://www.ncbi.nlm.nih.gov/pubmed/18076674?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: January 2015
Published: February 23, 2015